catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: If18cc0293b52ce5f7f8e068688aa17d28ed27d50
diff --git a/command/open_session.cpp b/command/open_session.cpp
index a7b75bf..f88f433 100644
--- a/command/open_session.cpp
+++ b/command/open_session.cpp
@@ -83,7 +83,7 @@
             static_cast<cipher::integrity::Algorithms>(request->intAlgo),
             static_cast<cipher::crypt::Algorithms>(request->confAlgo));
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
         response->status_code =
             static_cast<uint8_t>(RAKP_ReturnCode::INSUFFICIENT_RESOURCE);